Rock drill rotation mechanism



May 30, 1944. E. B. LEAR 2,349,971 w I RQCK DRILL RQTATION MECHANISM Fil'ed D96. 3. 1942 INVENTOR EAR B. LEAR ATTORNEY Patented May 30, 1944 S PATENT OFFICE Roox pmLL ROTATION MECHANISM Earl B; Lear, Garfield Heights, Ohio, assignor, by -mesne assignments, to The Cleveland Pneumatic ToolCompanwCleveland, Ohio, a corporation of Ohio Application December 3, 1942, Serial No. 467,753

' 4 Claims.

actuated rock drills of the reciprocatory piston type, and more particularly to improvements in the rotation mechanism usually incorporated in such rock drills for rotating the drill steel.

An important object of the invention resides I in the provision of. a rotation mechanism for rock drills having component part's of relatively simple design which mayreadily be assembled and disassembled without necessitating the use of special tools. Another object of the invention is to provide a rotation mechanism of the above character that is capable of instantaneous action to effect rotation of the drill steel upon movement of the piston in one direction whereby the cutting edges of the former are moved appropriately between successive blows so that maximum efliciency in drilling is secured. A further object of the invention is to provide a rock drill with a rotation mechanism that comprises relatively few parts, each of which is characterized by simplicity and ruggedness of construction thereby minimizing initial cost of manufacture and rendering unlikely damage other than resultant from ordinary use. A still further object of the invention is to providea rotation mechanism of the above character including the use of radially slidable plungers which cooperate with a specially designed head to effect rotation of the piston and which will provide a positive action for the plungers While eliminatingthe use of springs or the like for normally urging the plungers' into operative engagement.

Other objects and advantages more or less ancillary to the foregoing reside in the specific construction and aggroupment'of' the elements peculiar to this structure, as will become apparent from a more complete examination of this speci a flcation.

In the drawing which illustrates the invention: Fig. 1 is a side elevational view,.partly in section, of a rock drill embodying the features of'the present invention. Y

Fig. 2 is an enlarged horizontal sectionalview I (0]. 121-7) The present invention relates broadly to fiuid 4 a cylinder 9 formed with a piston chamber ID in which is reciprocably mounted a piston H. The piston II is formed with a shank 12 extending downwardly therefrom and slidable through a bushing l3, which bushing forms the lower end of chamber I0.

A front housing I4 is clampedto the cylinder 9 by means of bolts l5, in which is mounted the usual chuck sleeve and bushing (not shown) adapted to receive the shank of a drill steel l6 which ismounted in said bushing against relative rotation thereto. The shank l2 of the piston II is normally splined with the chuck for transmitting rotation thereto in a manner well known in this art.

The upper end of the cylinder I0 is formed with a counterbore, [1 on the bottom of which rests a valve block l8. Seated on the valve block I8 is a valve casing l9 within which is reciprocably mounted a fluid actuated valve 20 for controlling the admission of fluid to alternate ends of the cylinder [0. The improved rotation mechanism, to be hereinafter more fully described, is generally designated by the numeral 2|, the same being disposed within the counterbore 11 above the valve casinglS. A bearing plate 22 is seated upon the mechanism 2| engaged by a back head 23 which is clamped thereon through the side rods IS. A throttle valve (not shown) is mounted in the back head 23 and is operated by the lever 24 for controlling the admission of fluid to the valve casing 19 from where, under the control of thevalve 20, it travels to alternate ends of the cylinder ID for actuating the piston l I in a manner well known in the art.

The rotation mechanism, in accordance with the present invention, includes a ratchet ring 25 resting on the valve casing l9 and held against rotation relative to the cylinder 9 by a dowel pin 25. The ring 25 is formed with internal teeth 21. A rifled'or helically splined stem 28 extends upwardly from the piston I I and cooperates with a rifled nut (not shown) screwed within the head of the piston for rotating the same. The rifled stem 28 extends through the valve block and casing l8 and I9, respectively, and carries a head 29 which is encircled by the ratchet ring 25. A

'floating ring 30 is mounted between the head 29 The inner periphery of the ring 30 is formed with a series of inwardly extending teeth 33 having right angular bearing surfaces 34 adapted to plunger is disposed between a pair of teeth 34 and adjacent the side opposite the bearing surfaces 34. In the formation of the teeth 33, one wall 33 thereof slants inwardly for a predetermined distance and is united with the right angular bearing surface 34 through an arcuate surface 31.

As before indicated, the teeth .35 .of the head 29 engage the teeth 33 of the ring "30, said teeth 35 being likewise formed with right angular :bearing surfaces 33. The periphery of the teeth :35 is of such contour as to be in constant engagement with the inner wall of the ring 30, as clearly shown in Figs. 2 and 3. Thearea of thehead 29 between the teeth 35 is formed with a pair of continuous cam surfaces 39 and 40, adapted to alternately engage the plungers 32 and arcuate surfaces 3.! of the teeth 33. Rotation of the head 29 in a clockwise direction in Fig. '2 will effect engagement of the cam surfaces 139 and 40 with the plungers 32 to slide the latteroutwardlyinto engagement with the gear teeth 21. However, rotation of the head 29 in a counterclockwise direction in Fig. 3 will bring the right angularbearing surfaces 34 and 38 of the teeth 33 and 35, respectively, into engagement permitting withdrawal of the plungers 32 from the gear teeth 21, whereby the 'head 29 ring 39 and rifled stem 28 are free to rotate in unison.

In the operation of the mechanism. as the lever 24 i actuated to open the throttle valve, motive fluid therefrom is free to new to the valve 20 where it is. alternately admitted into the ends of the piston chamber ,for effecting reciprocation of the piston H and the consequential delivery of impacts on the drill steel l6.

As shown in Fig. 1, the stem .28 is provided with a hight hand helical spline which cooperatse with a similar spline provided in the rifled nut screwed within the piston I]. therebytending, during the strokes of the piston toward the valve block 18, to rotate thestem 2.8 .and its head 29 in a clockwise direction in .2. Assuming that the piston .II has completed its forward stroke, .on the return or reaward stroke, the stem 28 and head 29 will begin to turn in a clockwise direction. As the head 2.9 is rotated, the cam surfaces 39 and .40 contact the plungers 32 urging said plungers outwardly into engagement with the ratchet teeth 2]. Engagement of the plungers with the ratchet teeth will lock the ring so and head 29 thereby preventing further rotation of the stem 28 and head 29 in aclockwise direction, and causing the piston during its rearward strokes to rotate in the other direction. From the piston, rotation is transmitted to the drill steel I 6 through the chuck sleeve and bushing (not shown) in the manner well known in the art.

During the forward strokes of the piston, the stem 28 and head29 will rotate in a counterclockwise direction in 3 and the parts will move from the position shown in Fig. .2 to that shown in Fig. 3. At that time the right angular bearing surfaces 38 of the teeth 35 will contact the right angular bearing surfaces '34 .of the teeth 33 to effect rotation of the ring 30 and disengagement of the plungers .32 from the ratchet teeth 21. As is to be understood, the plungers 32 are freely slidable within the slots 3| and, as the ring 30 is rotated by the head 29,

said plungers will be free to slide out of engagement with the ratchet teeth 21 since contact will then be had with the low spot of the cam surfaces 39 and 40 as clearly shown in Fig. 3. In this instance, the piston I I will be driven forwardly without rotation for delivering impacts to the drill steel in rapid succession.

From the foregoing explanation, .it will be understood that an improved means has been ':provided for automatically imparting rotation to thepiston and drill steel so that the cutting edges of the steel are moved appropriately between .successive :blows so that maximum effi- .ci'encys'mzdrillingis secured. The teeth 35 and .camsurfacesfiflnnd 40 on the head 29 are formed so as' to aotivelyengage the teeth of the floating ring .30 and plungers carried thereby as said head is rotated in either a clockwise or counterclockwise direction during reciprocation of the piston. I

Although the foregoing description is necessarily of .a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to Joe restrictive or confining and it is .toibe further understood that various rearrangements of parts .and modifications of structural detail .may lbe resorted to without departing .fromthe scope or .spirit of the invention as herein claimed.

I claim:

1. .In [a rock drill, a cylinder having a piston ,reoiprocahle therein and capable of rotation, -a ratchet ring .fixedly mounted in said cylinder, a rotation mechanism for said piston including a rifled stem operatively associated therewith, a head .on said stem, .a member disposed between said head and ratchet ring and movable with said head, and means carried by said member adapted to engage said ratchet ring for effecting rotation of said piston during its strokes in one direction.

2. In a rock .drill, a cylinder having a piston reciprocable therein and capable of rotation, a ratchet ring mounted in said cylinder, a rotation mechanism for said piston including a rifled stem operatively associated therewith, a head on said stem, a ring freely mounted between said head and ratchet ring, plungers slidably carried by saidring adapted to engage said ratchet ring during the strokes of said piston in (one direction, and means forming a part of said head for urging said plungers into engagement with said ratchet ring, whereby rotation 'of said piston is effected during its strokes in one direction.

3. In :a rock drill, a cylinder having a piston reciprocable therein and capable of rotation, a ratchet ring mounted in said cylinder, a rotation mechanism for said piston including a rifled stem-.operatively associated therewith, a head on said stem, a ring freely mounted between said head and ratchet ring, plungers slidably carried by said ring adapted to engage said ratchet ring "during the strokes of said piston in one direction. a series of teeth formed on the inner periphery of said ring, a series of teeth formed on the outer periphery of said head adapted to engage said ring teeth during the strokes of said piston in one direction, and cam means on said head for urging said plungers into engagement with said ratchet ring, whereby rotation of said piston is efiected during its strokes in one direction.

4.. In a rock drill, a cylinder having a piston reciprocable therein, a ratchet ring fixedly mounted in said cylinder, a rotation mechanism for said piston including a rifled stem operatively associated therewith, a head on said stem, a member disposed between said head and ratchet ring and rotatable with said head in one direction only, a series of spaced radially slidable plungers carried by said member and adapted to engage said ratchet ring during the strokes of said piston in one direction, and means on said head for urging said plungers radially into engagement with said ratchet ring during said one direction of the piston for locking said Head and rifled stem to permit rotation of said piston in said one direction.

EARL B. LEAR. 

